Android Simple Calculator

This is a long time ago, the method is very simple, are some basic, but there are many areas need to improve.

Activity_main.xml layout:

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"Android:layout_width="fill_parent"Android:layout_height="fill_parent"android:orientation="Vertical"> <EditText Android:id="@+id/edittext1"Android:layout_width="match_parent"Android:layout_height="wrap_content"Android:ems="Ten"> <requestfocus/> </EditText> <LinearLayout android:layout_width="match_parent"Android:layout_height="wrap_content"> <Button Android:id="@+id/button1"Android:layout_width="wrap_content"Android:layout_height="wrap_content"Android:onclick="ButtonClick"Android:text="+"Android:textcolor="#000fff"android:textsize="20DP"/> <Button Android:id="@+id/button2"Android:layout_width="wrap_content"Android:layout_height="wrap_content"Android:onclick="ButtonClick1"Android:text="-"/> <Button Android:id="@+id/button3"Android:layout_width="wrap_content"Android:layout_height="wrap_content"Android:onclick="ButtonClick2"Android:text="*"/> <Button Android:id="@+id/button4"Android:layout_width="wrap_content"Android:layout_height="wrap_content"Android:onclick="ButtonClick3"Android:text="/"/> </LinearLayout> <EditText Android:id="@+id/edittext2"Android:layout_width="match_parent"Android:layout_height="wrap_content"Android:ems="Ten"/> <TextView Android:id="@+id/textview1"Android:layout_width="wrap_content"Android:layout_height="wrap_content"android:textsize="40DP"Android:text="="/> <EditText Android:id="@+id/edittext3"Android:layout_width="match_parent"Android:layout_height="wrap_content"Android:textcolor="#ff0000"Android:ems="Ten"/></linearlayout>

Mainactivity:

Package Com.example.jisuanqi;import android.os.bundle;import android.app.activity;import android.view.Menu; Import Android.view.view;import Android.view.view.onclicklistener;import Android.widget.button;import Android.widget.EditText; Public classmainactivity extends Activity {button button; @Overrideprotected voidonCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);                Setcontentview (R.layout.activity_main); //additionButton button=(Button) Findviewbyid (R.id.button1); Button.setonclicklistener (NewOnclicklistener () {@Override Public voidOnClick (View arg0) {//TODO auto-generated Method StubEditText ed1=(EditText) Findviewbyid (R.ID.EDITTEXT1); EditText Ed2=(EditText) Findviewbyid (R.ID.EDITTEXT2); EditText ed3=(EditText) Findviewbyid (R.ID.EDITTEXT3); intnum1=Integer.parseint (Ed1.gettext (). toString ()); intNum2=Integer.parseint (Ed2.gettext (). toString ()); intnum3=num1+num2;            Ed3.settext (string.valueof (num3));        }        }); //SubtractionButton button2=(Button) Findviewbyid (R.id.button2); Button2.setonclicklistener (NewOnclicklistener () {@Override Public voidOnClick (View arg0) {//TODO auto-generated Method StubEditText ed1=(EditText) Findviewbyid (R.ID.EDITTEXT1); EditText Ed2=(EditText) Findviewbyid (R.ID.EDITTEXT2); EditText ed3=(EditText) Findviewbyid (R.ID.EDITTEXT3); intnum1=Integer.parseint (Ed1.gettext (). toString ()); intNum2=Integer.parseint (Ed2.gettext (). toString ()); intNum3=num1-num2;            Ed3.settext (string.valueof (num3));        }        }); //multiplicationButton button3=(Button) Findviewbyid (R.id.button3); Button3.setonclicklistener (NewOnclicklistener () {@Override Public voidOnClick (View arg0) {//TODO auto-generated Method StubEditText ed1=(EditText) Findviewbyid (R.ID.EDITTEXT1); EditText Ed2=(EditText) Findviewbyid (R.ID.EDITTEXT2); EditText ed3=(EditText) Findviewbyid (R.ID.EDITTEXT3); intnum1=Integer.parseint (Ed1.gettext (). toString ()); intNum2=Integer.parseint (Ed2.gettext (). toString ()); intNum3=num1*num2;            Ed3.settext (string.valueof (num3));        }        }); //DivisionButton button4=(Button) Findviewbyid (R.ID.BUTTON4); Button4.setonclicklistener (NewOnclicklistener () {@Override Public voidOnClick (View arg0) {//TODO auto-generated Method StubEditText ed1=(EditText) Findviewbyid (R.ID.EDITTEXT1); EditText Ed2=(EditText) Findviewbyid (R.ID.EDITTEXT2); EditText ed3=(EditText) Findviewbyid (R.ID.EDITTEXT3); intnum1=Integer.parseint (Ed1.gettext (). toString ()); intNum2=Integer.parseint (Ed2.gettext (). toString ()); intnum3=num1/num2;        Ed3.settext (string.valueof (num3));           }    }); } @Override Publicboolean Oncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.main, menu); return true; }    }

Android Simple Calculator